#pragma warning disable

namespace System.Diagnostics.CodeAnalysis;

#if NETSTANDARD2_0
/// <summary>
/// Specifies that null is allowed as an input even if the corresponding type disallows it.
/// </summary>
[AttributeUsage(AttributeTargets.Field | AttributeTargets.Parameter | AttributeTargets.Property, Inherited = false)]
internal sealed class AllowNullAttribute : Attribute
{ }

/// <summary>
/// Specifies that null is disallowed as an input even if the corresponding type allows it.
/// </summary>
[AttributeUsage(AttributeTargets.Field | AttributeTargets.Parameter | AttributeTargets.Property, Inherited = false)]
internal sealed class DisallowNullAttribute : Attribute
{ }

/// <summary>
/// Specifies that an output may be null even if the corresponding type disallows it.
/// </summary>
[AttributeUsage(AttributeTargets.Field | AttributeTargets.Parameter | AttributeTargets.Property | AttributeTargets.ReturnValue, Inherited = false)]
internal sealed class MaybeNullAttribute : Attribute
{ }

/// <summary>
/// Specifies that an output will not be null even if the corresponding type allows it.
/// Specifies that an input argument was not null when the call returns.
/// </summary>
[AttributeUsage(AttributeTargets.Field | AttributeTargets.Parameter | AttributeTargets.Property | AttributeTargets.ReturnValue, Inherited = false)]
internal sealed class NotNullAttribute : Attribute
{ }

/// <summary>
/// Specifies that when a method returns <see cref="ReturnValue"/>, 
/// the parameter may be null even if the corresponding type disallows it.
/// </summary>
[AttributeUsage(AttributeTargets.Parameter, Inherited = false)]
internal sealed class MaybeNullWhenAttribute : Attribute
{
    /// <summary>
    /// Initializes the attribute with the specified return value condition.
    /// </summary>
    /// <param name="returnValue">The return value condition. If the method returns this value, the associated parameter may be null.</param>
    public MaybeNullWhenAttribute(bool returnValue) => ReturnValue = returnValue;

    /// <summary>
    /// Gets the return value condition.
    /// </summary>
    public bool ReturnValue { get; }
}

/// <summary>
/// Specifies that when a method returns <see cref="ReturnValue"/>, 
/// the parameter will not be null even if the corresponding type allows it.
/// </summary>
[AttributeUsage(AttributeTargets.Parameter, Inherited = false)]
internal sealed class NotNullWhenAttribute : Attribute
{
    /// <summary>
    /// Initializes the attribute with the specified return value condition.
    /// </summary>
    /// <param name="returnValue">The return value condition. If the method returns this value, the associated parameter will not be null.</param>
    public NotNullWhenAttribute(bool returnValue) => ReturnValue = returnValue;

    /// <summary>
    /// Gets the return value condition.
    /// </summary>
    public bool ReturnValue { get; }
}

/// <summary>
/// Specifies that the output will be non-null if the named parameter is non-null.
/// </summary>
[AttributeUsage(AttributeTargets.Parameter | AttributeTargets.Property | AttributeTargets.ReturnValue, AllowMultiple = true, Inherited = false)]
internal sealed class NotNullIfNotNullAttribute : Attribute
{
    /// <summary>
    /// Initializes the attribute with the associated parameter name.
    /// </summary>
    /// <param name="parameterName">The associated parameter name.  The output will be non-null if the argument to the parameter specified is non-null.</param>
    public NotNullIfNotNullAttribute(string parameterName) => ParameterName = parameterName;

    /// <summary>
    /// Gets the associated parameter name.
    /// </summary>
    public string ParameterName { get; }
}

/// <summary>
/// Applied to a method that will never return under any circumstance.
/// </summary>
[AttributeUsage(AttributeTargets.Method, Inherited = false)]
internal sealed class DoesNotReturnAttribute : Attribute
{ }

/// <summary>
/// Specifies that the method will not return if the associated Boolean parameter is passed the specified value.
/// </summary>
[AttributeUsage(AttributeTargets.Parameter, Inherited = false)]
internal sealed class DoesNotReturnIfAttribute : Attribute
{
    /// <summary>
    /// Initializes the attribute with the specified parameter value.
    /// </summary>
    /// <param name="parameterValue">The condition parameter value. Code after the method will be considered unreachable by diagnostics if the argument to the associated parameter matches this value.</param>
    public DoesNotReturnIfAttribute(bool parameterValue) => ParameterValue = parameterValue;

    /// <summary>
    /// Gets the condition parameter value.
    /// </summary>
    public bool ParameterValue { get; }
}
#endif

#if NETSTANDARD2_0 || NETSTANDARD2_1
/// <summary>
/// Specifies that the method or property will ensure that the listed field and property members have not-null values.
/// </summary>
[AttributeUsage(AttributeTargets.Method | AttributeTargets.Property, Inherited = false, AllowMultiple = true)]
internal sealed class MemberNotNullAttribute : Attribute
{
    /// <summary>
    /// Initializes the attribute with a field or property member.
    /// </summary>
    /// <param name="member">The field or property member that is promised to be not-null.</param>
    public MemberNotNullAttribute(string member) => Members = new[] { member };

    /// <summary>
    /// Initializes the attribute with the list of field and property members.
    /// </summary>
    /// <param name="members">The list of field and property members that are promised to be not-null.</param>
    public MemberNotNullAttribute(params string[] members) => Members = members;

    /// <summary>
    /// Gets field or property member names.
    /// </summary>
    public string[] Members { get; }
}

/// <summary>
/// Specifies that the method or property will ensure that the listed field and property members have not-null values 
/// when returning with the specified return value condition.
/// </summary>
[AttributeUsage(AttributeTargets.Method | AttributeTargets.Property, Inherited = false, AllowMultiple = true)]
internal sealed class MemberNotNullWhenAttribute : Attribute
{
    /// <summary>
    /// Initializes the attribute with the specified return value condition and a field or property member.
    /// </summary>
    /// <param name="returnValue">The return value condition. If the method returns this value, the associated parameter will not be null.</param>
    /// <param name="member">The field or property member that is promised to be not-null.</param>
    public MemberNotNullWhenAttribute(bool returnValue, string member)
    {
        ReturnValue = returnValue;
        Members = new[] { member };
    }

    /// <summary>
    /// Initializes the attribute with the specified return value condition and list of field and property members.
    /// </summary>
    /// <param name="returnValue">The return value condition. If the method returns this value, the associated parameter will not be null.</param>
    /// <param name="members">The list of field and property members that are promised to be not-null.</param>
    public MemberNotNullWhenAttribute(bool returnValue, params string[] members)
    {
        ReturnValue = returnValue;
        Members = members;
    }

    /// <summary>
    /// Gets the return value condition.
    /// </summary>
    public bool ReturnValue { get; }

    /// <summary>
    /// Gets field or property member names.
    /// </summary>
    public string[] Members { get; }
}
#endif

#pragma warning restore